The long term goal of this project is to establish psychometrically credible outcome measures for RTT clinical trials based on the relevant to core and supporting diagnostic domains. To achieve this end, the short-term goal of this project is to establish the psychometric properties for three non-invasive, objective clinical assessment measures of clinically-relevant symptoms. The project will achieve this objective by evaluating internal and test-retest reliability and preliminary convergent validity evidence for an objective, non-invasive method of evaluating peripheral vasomotor function using portable infrared thermography (IRT; Aim 1), an objective measure of sleep patterns using in-home wrist-based actigraphy (ACT; Aim 2), and an objectively scored assessment of gain/loss of tactile sensitivity in response to a standardized set of calibrated tactile stimuli (mQST; Aim 3). Based on our pilot work, in which we have documented the feasibility of all three measures, we anticipate that all three measures will show adequate internal reliability, and that test-retest reliability will vary between variables derived from each method. Completion of the proposed project will lead to optimized quantification methods for each of the proposed measures, and empirical estimates of reliability, which can be used as a foundation for power analyses for future clinical trials in RTT for interventions with anticipated effects on sleep, autonomic function, and/or somatosensory function.